Such a motor vehicle seat is known from the patent EP 265 747. With this motor vehicle seat a catch arm, which carries a gear tooth forming, and which extends upward in a straight line, is linked to the underframe, especially at a longitudinal adjustment device of the underframe. It is encompassed by a support part onto which the belt lock is attached. The support part can be shifted towards the catch arm. When exposed to an overload due to an accident, the support engages into the gear tooth forming of the catch arm and effects a locking. The support part is linked to the seat support.
This arrangement has proven to be generally effective. It needs a connection to the underframe, however, especially to a seat carrier of the longitudinal adjustment device. This connection is effected by a catch arm. Furthermore, when adjusting the seat carrier towards the underframe, a shifting between the support part and the catch arm occurs each time, the powers effecting this shift always have a component, which extends in a parallel manner to the direction of contact from the support part and the catch arm.
This is where the invention starts. It is the task of the invention to further develop a motor vehicle seat of the above mentioned kind in such a way that an adjustment of the seat support towards the longitudinal adjustment device cannot lead to a contact of the contact area and the gear tooth forming, but rather that a mostly constant clearance and for that reason also a clearance, which can be embodied in a very small manner remains independent of any respective adjustment between the area of contact and the tooth gear forming.
This task is solved by the fact that a) at the swiveling support a tooth segment is embodied, which extends to the swiveling joint in a concentric manner that b) the belt lock is linked to the seat support via an L-shape connecting part, which has a first arm, extending essentially in the direction of the belt lock and a second arm, which extends thereto in a crosswise manner and which is attached to the seat support in a swiveling manner in an articulated joint, which is provided in the distance of the first arm at the second arm that c) the connecting part comprises an area of contact, which is allocated to the tooth segment and which in its normal position is in distance from the tooth segment by a small clearance, but which can engage at the belt lock into the tooth segment in such a way that it catches the tooth segment, when exposed to stress caused by an accident.
With this motor vehicle seat the safety belt tensile forces, which acts upon the belt lock, are induced via the connecting part connected with the same and the area of contact thereof directly into the back support swing, which again guide these forces into the longitudinal adjustment device. A separate part like the catch arm is not necessary according to the state of the art. Due to that, an additional part becomes obsolete, which normally connects the seat support and the longitudinal adjustment device and whose freedom of movement needs to be protected on one hand and guaranteed on the other, which leads to an additional spatial requirement, additional weight and the necessity of random checks.
According to the invention these construction components, which effect an intercrossing caused by an accident and thereby a connection of tensile strength between the belt lock and the back support swing, are explicitly small and arranged exclusively in the area of the seat support. They move with the same. The tooth segment always has the same distance to the area of contact, because the tooth area extends to the swiveling area in a concentric manner and the connecting part is arranged at the seat support with its area of contact. The relative movement and thereby the allocation between area of contact and tooth segment is mechanically more favorable than according to the state of the art, which leads to more defined relations of contact with safety belt tensile forces caused by an accident independent from the relative positions of the individual parts and to construction and function, which can be mechanically better controlled. The contact paths can also be embodied in a shorter manner. The contact may also be reversible even with lower safety belt tensile forces.
It has proven to be advantageous to have a gear tooth forming at the tooth segment embodied in a saw-toothed shape. A decisive factor is the fact that the flanks of the teeth of the tooth segment, which extend crosswise to the direction of the tensile forces and which form the blocking flank when exposed to tensile stress, extend in an angle to the direction to the direction of the tensile force, which is sufficiently large, so that there is no risk of the contact area sliding out of the tooth segment on its own accord.
It has proven to be advantageous to join the first arm and the second arm via a joint. Both arms can basically be connected with each other in a rigid manner. During the process of contact the direction of the first arm does not change with a joint connection.
In a preferred embodiment the tooth segment is embodied on a ring area. This ring area is closely encompassed by an area of contact embodied in an O-shape manner. By this the area of contact is allocated in such a way that it offers extensive security and that it is opened only after the destruction of at least one part. An evasion to the side of the area of contact during the phase of stress and thereby a release of the area of contact from the tooth segment is avoided that way.
In a preferred embodiment the connecting part is kept in its normal position by a spring. The spring is embodied sufficiently weak that it has no effect on the safety belt lock with tensile forces caused by an accident. It is much rather embodied in an advantageous manner in such a way that it is overcome already with a light car accident and thereby the area of contact can engage into the teeth of the tooth segment. By this, this contact can occur already with a delay of 3 g (1 g corresponding to 10 m s.sup.-2). Typical accelerations caused by an accident are at -10 g and above.
It is also possible to arrange the connecting part, which is destroyed when overexposed to stress caused by an accident, by a support part to the seat support and thereby to keep it in the normal position. That way for example, the connecting part can be connected to the seat support via a pin, which shears off when exposed to stress caused by an accident.
The construction of the motor vehicle seat according to the invention makes it possible to adjust the safety belt lock in dependence of the angular position of the back swiveling support in a different way with regard to the seat support. The relative movement between the tooth segment (and thereby swiveling support) and the connecting part, as it may appear when adjusting the angle inclination of the back swiveling support, can actually be influenced for an influence of the angular position of the belt lock via a more or less strong receiver of the first arm by the swiveling support.
In a preferred embodiment a) a lower articulated area of the swiveling support at a longitudinal adjustment device, b) the area of contact and c) the belt lock lay essentially above each other or in the direction of the tensile forces, which act upon at the safety belt lock. That way the high safety belt forces caused by an accident are induced favorably into the longitudinal adjustment device and thereby also into the understructure of the pertaining motor vehicle. It has proven to be advantageous, if the two mentioned areas and the safety belt lock are essentially on a straight line. In the course of the adjustment area of the back swiveling support these conditions already mentioned are more or less fulfilled.
Further advantages and characteristics of the invention derive from the other claims as well as the following description of a non-restrictive embodiment of the invention, which is illustrated further with regard to the drawing. This drawing shows in: